Magnetic separator



April 29, 1958 K. NEUMANN A. GoLTz ETAL 2,832,471

MAGNETIC SEPARATOR Filed Jan. 15, 1957 United States Patent 2,832,471 MAGNETIC SEPARATOR Arnold Goltz, Salzgitter-Gebhardshagen, and Kurt Neumann, Salzgitter-Bad, Germany, assignors to Erzbergban Salzgitter Aktiengesellschaft, Salzgitter-Bad, Germany Application January 15, 1957, Serial No. 634,343 Claims priority, application Germany June 8, 1956 2 Claims. (Cl. 209-219) This invention concerns magnetic separators, and relates particularly to a separator having two rotating extraction rollers for the magnetic separation of granular materials, especially weakly magnetic ores, in which each extraction roller forms a pole of a magnet frame.

Magnetic separators of this type are known, in which there is associated with each extraction roller acting as the one pole of the magnet frame, a separate, stationary counter pole. Between these two poles there is arranged an air space through which passes the material to be separated. The separate arrangement of a stationary counter pole for each extraction roller results in a disproportionately bulky shape of the magnet frame, which must hence, as a rule, be provided with a three-legged support.

In contrast to this substantial constructional simplification of the magnet frame is achieved according to the present invention in that the two staionary counter poles form a common centre or core for the poles constituted by the extraction rollers, which core is so arranged between the two extraction rollers as to form two air spaces for the passage of the material undergoing separation. In this way the two air spaces for the passage of the the material may be compactly arranged adjacent one another in a simple magnet frame, which, as compared with a separator having two adjacently disposed rollers without a stationary counter pole, has the advantage of presenting an effectively lengthier separating zone and hence a throughput capacity of the order of 50% higher. Furthermore the magnetic dispersion is reduced and hence also the excitation power required. The intermediate core also makes it possible completely to isolate the magnetic neutral zone by the application of non-magnetic material (e. g. Remanit) to the surfaces facing the extraction rollers. Finally the tractive force which acts on the rollers, which under some circumstances can be very high, is compensated.

In one particular form of construction of the invention, the intermediate core is provided with grooves on its two sides which face the extraction rollers, which grooves preferably extend parallel to the axis of the extraction rollers. By means of these grooves, the convergence of the magnetic field can be considerably increased at one or more positions along the air spaces on both sides of the grooves; at the same time the induction on both sides of the grooves can be raised with constant magnetic flux. Moreover the magnetic field is considerably attenuated at the positions of the grooves, themselves so that magnetic material which has already adhered to the extraction rollers, is once again loosened and re-arranged. In this way, non-magnetic particles which have perhaps been trapped are freed and thrown ofi, whereby an increased degree of separation and greater throughput capacity are attained.

The grooves of the intermediate core are preferably filled in or covered by non-magnetic material. Sticking of the material to be separated in the grooves and hence stopping up of the air passages for this material, are thereby avoided.

The invention will be described further, by way of example, with reference to the accompanying drawing, which is a diagrammatic sectional elevation of one magnetic separator constructed in accordance with the invention.

On the magnet frame 1, which has an exciting coil not shown in the drawing, are arranged two extraction rollers 2, which rotate oppositely to one another and which in the usual way may be fluted. Between the two extraction rollers 2 is located a common centre or core 3, which constitute the counter poles to the poles formed by the rollers 2. The intermediate core 3 is provided on its two sides which face the extraction rollers 2 with grooves 4, which are covered by means of a non-magnetic plate 5, e. g. of Remanit.

Above the intermediate core 3 is provided a housing 6 which is connected to a pressure air conduit 7. The housing 6 is closed at the top in a roof-like manner, as by means of air-permeable plates 8.

The material to be separated falls on both sides of the housing 6 in the direction of the arrow X into the two air spaces 9, where separation takes place. Non-magnetic separated material is led away in the direction of the arrow Y, whilst magnetic separated material is accumulated in the direction of the arrows Z.

We claim:

1. A magnetic separator for granular material, comprising a pair of mutually spaced, oppositely rotating extraction rollers, and a common magnetisable central core arranged between said rollers, the surfaces of the core facing said rollers conforming closely to the circumferential surfaces of the rollers themselves to form slitlike separation zones therewith, said core surfaces each having formed therein, at least one groove extending parallel to the axis of said extraction rollers and said core having its magnetic induction accompilshed by said rollers via said zones.

2. A magnetic separator as set forth in claim 1, wherein said grooves are covered by a non-magnetic material.

References Cited in the file of this patent UNITED STATES PATENTS 641,148 Payne Jan. 9, 1900 832,822 Wait et al. Oct. 9, 1906 2,678,729 Spodig May 18, 1954 FOREIGN PATENTS 646,229 Germany June 10, 1937 

